Radiation Therapy for Small Cell Lung Cancer: An ASTRO Clinical Practice Guideline

Role of stereotactic radiotherapy in the management of small-cell lung cancer

Small-cell lung cancer is the most aggressive form of lung neoplasia, treated in recent decades with chemoradiotherapy in case of limited stage and chemotherapy alone at the metastatic stage. In the last few years, the advent of immunotherapy has changed the landscape in the treatment of non-small-cell lung cancer, and to a lesser degree in small-cell lung cancer. Despite the recent advances in research, small-cell lung cancer is still considered an aggressive and lethal disease characterized by high recurrence or metastatic potential. As stereotactic radiotherapy has established itself as the standard of care in the early stage of inoperable non-small-cell lung cancer and in metastatic disease to treat brain and extracranial metastases, these same issues now arise in the management of small-cell lung cancer. This article aims to review the current knowledge and the potential of stereotactic radiotherapy in small-cell lung cancer.

Evaluation of Radiation Therapy Treatment Plans in a Randomized Phase 2 Trial Comparing 2 Schedules of Twice-Daily Thoracic Radiation Therapy in Limited Stage Small Cell Lung Cancer

PURPOSE

There is limited clinical data for recommendations on how to deliver thoracic radiation therapy (TRT) concurrently with chemotherapy in limited-stage small cell lung cancer. We reviewed radiation therapy treatment plans in a randomized phase 2 trial comparing high-dose with standard-dose twice-daily TRT to assess treatment planning techniques, dose-volume data for target volumes and organs at risk (OARs), evaluate compliance with the protocol, associations with radiation-induced toxicity, and whether an imbalance in treatment planning parameters might be a reason for the large survival benefit of the higher dose (median overall survival 43.6 vs 22.6 months).

METHODS AND MATERIALS

In the study, 170 patients were to receive 4 courses of platinum/etoposide and were randomized to receive twice-daily TRT of 60 Gy/40 fractions (fx) or 45 Gy/30 fx. TRT treatment plans for those who received 1 or more fx of TRT (n = 166) were analyzed.

RESULTS

The most common treatment planning technique was 3-dimensional conformal radiation therapy (67%). The 75th percentile of the reported dose-volume parameters for the OARs were within the protocol-recommended limits for both groups. Mean doses to the esophagus of 25.5 Gy (IQR, 20.2-31.3; 60 Gy/40 fx) and 24.3 Gy (IQR, 20.3-27.5; 45 Gy/30 fx) were associated with 21% and 18% ≥ grade 3 acute esophagitis, respectively. In the 60 Gy/40 fx group, a mean dose to the lungs of 16.5 Gy (IQR, 15.8-16.9), V20 Gy of 29.5% (IQR, 28.8-30.4), and V5 Gy of 65.6% (IQR, 61.5-68.7) led to ≥ grade 3 pneumonitis in 4% of the patients. There was no ≥ grade 3 pneumonitis in the 45 Gy/30 fx group. The treatment planning techniques, the percentage change in volumes between original and redelineated OARs, planning target volumes, relative doses, and laterality were well balanced between the randomly assigned groups.

CONCLUSIONS

Considering the incidences of severe radiation-induced toxicities were within the range of other recent trials, the reported doses to the OARs appear to be safe. Treatment planning parameters were well balanced between the randomly assigned groups, supporting that the survival benefit of the twice-daily 60 Gy/40 fx TRT schedule was due to the higher dose.

Analysis of intra-fractional positioning correction performed by cone beam computed tomography in SBRT treatments

PURPOSE

This study aims to evaluate the positioning correction extracted from Intra-fraction Cone Beam (IF-CBCT) images obtained during Stereotactic Body Radiotherapy (SBRT) treatments, and to assess whether its magnitude justifies its acquisition. In addition, the results obtained in lung, liver, and pancreas SBRTs with two deep inspiration breath-hold systems (DIBH), and for prostate with/without ultrasound (US) monitoring were compared.

METHODS

1449 treatments, performed with two linear accelerators (LINACs) were retrospectively analyzed. DIBH were performed either with a spirometry-based device or a surface-guidance system and one LINAC was equipped with US monitoring system for prostate. Significance tests were used to account for differences between units.

RESULTS

Group systematic error (M) was approximately -0.7 mm for DIBH treatments in superior-inferior (SI) direction with no difference (p > 0.7) between LINACs. Moreover, there was a SI difference of 0.5 mm for prostate treatments (p = 0.008), in favor of the US monitored one. In anterior-posterior (AP) direction, only liver treatments exhibited differences between LINACs, with the spirometer-based system being 0.8 mm inferior (p = 0.003). M<0.4 mm in left-right (LR) direction was found for all locations and LINACs. The spirometer-based system resulted in lower standard deviation of systematic and random errors in most components and locations, with a greater effect observed in liver SBRTs.

CONCLUSIONS

The corrections made with IF-CBCT during SBRT treatments were not negligible. Both DIBH systems were effective in managing respiratory movements. However, the spirometry-based system was slightly more accurate. In addition, US monitoring of the prostate appeared to be useful in reducing target shift.

Long-Term Outcomes After Concurrent Once- or Twice-Daily Chemoradiation in Limited-Stage Small Cell Lung Cancer: A Brief Report From the CONVERT Trial

PURPOSE

CONVERT was a phase 3 international randomized clinical trial comparing once-daily (OD) and twice-daily (BD) radiation therapy (RT). This updated analysis describes the 6.5-year outcomes of these regimens delivered with conformal techniques.

METHODS AND MATERIALS

CONVERT (NCT00433563) randomized patients 1:1 between OD RT (66 Gy/33 fractions/6.5 weeks) and BD RT (45 Gy/30 fractions/3 weeks), both delivered with concurrent cisplatin/etoposide. Three-dimensional conformal RT was mandatory, intensity-modulated RT was permitted, and elective nodal irradiation was not allowed. Prophylactic cranial irradiation was delivered at the discretion of treating clinicians. RT treatment planning was subject to central quality assurance.

RESULTS

Five hundred forty-seven patients were recruited at 73 centers. The median follow-up for the surviving cohort (n = 164) was 81.2 months. The median survival for the OD and BD arms were 25.4 months (95% CI, 21.1-30.9) and 30.0 months (95% CI, 25.3-36.5; hazard ratio, 1.13; 95% CI, 0.92-1.38; P = .247). Performance status and tumor volume were associated with survival on multivariate analysis. No treatment-related deaths occurred subsequent to the initial analysis performed in 2017. Regarding late toxicity, 7 patients in the OD arm developed grade 3 esophagitis, 4 of which went on to develop stricture or fistulation, compared with no patients in the BD arm. Grade 3 pulmonary fibrosis occurred in 2 and 3 patients in the OD and BD arms, respectively.

CONCLUSIONS

As the CONVERT trial did not demonstrate the superiority of OD RT and this regimen had a slightly worse toxicity profile after 80 months of follow-up, 45 Gy BD should remain the standard of care in limited stage small cell lung cancer.

Harnessing the Power of Radiotherapy for Lung Cancer: A Narrative Review of the Evolving Role of Magnetic Resonance Imaging Guidance

Compared with computed tomography (CT), magnetic resonance imaging (MRI) traditionally plays a very limited role in lung cancer management, although there is plenty of room for improvement in the current CT-based workflow, for example, in structures such as the brachial plexus and chest wall invasion, which are difficult to visualize with CT alone. Furthermore, in the treatment of high-risk tumors such as ultracentral lung cancer, treatment-associated toxicity currently still outweighs its benefits. The advent of MR-Linac, an MRI-guided radiotherapy (RT) that combines MRI with a linear accelerator, could potentially address these limitations. Compared with CT-based technologies, MR-Linac could offer superior soft tissue visualization, daily adaptive capability, real-time target tracking, and an early assessment of treatment response. Clinically, it could be especially advantageous in the treatment of central/ultracentral lung cancer, early-stage lung cancer, and locally advanced lung cancer. Increasing demands for stereotactic body radiotherapy (SBRT) for lung cancer have led to MR-Linac adoption in some cancer centers. In this review, a broad overview of the latest research on imaging-guided radiotherapy (IGRT) with MR-Linac for lung cancer management is provided, and development pertaining to artificial intelligence is also highlighted. New avenues of research are also discussed.

NRG Oncology and Particle Therapy Co-Operative Group Patterns of Practice Survey and Consensus Recommendations on Pencil-Beam Scanning Proton Stereotactic Body Radiation Therapy and Hypofractionated Radiation Therapy for Thoracic Malignancies

Stereotactic body radiation therapy (SBRT) and hypofractionation using pencil-beam scanning (PBS) proton therapy (PBSPT) is an attractive option for thoracic malignancies. Combining the advantages of target coverage conformity and critical organ sparing from both PBSPT and SBRT, this new delivery technique has great potential to improve the therapeutic ratio, particularly for tumors near critical organs. Safe and effective implementation of PBSPT SBRT/hypofractionation to treat thoracic malignancies is more challenging than the conventionally fractionated PBSPT because of concerns of amplified uncertainties at the larger dose per fraction. The NRG Oncology and Particle Therapy Cooperative Group Thoracic Subcommittee surveyed proton centers in the United States to identify practice patterns of thoracic PBSPT SBRT/hypofractionation. From these patterns, we present recommendations for future technical development of proton SBRT/hypofractionation for thoracic treatment. Among other points, the recommendations highlight the need for volumetric image guidance and multiple computed tomography-based robust optimization and robustness tools to minimize further the effect of uncertainties associated with respiratory motion. Advances in direct motion analysis techniques are urgently needed to supplement current motion management techniques.

Management of patients with extensive small-cell lung cancer in the immunotherapy era: An Italian consensus through a Delphi approach

BACKGROUND

Immunotherapy represented a turning point for treating extensive small-cell lung cancer (ES-SCLC). Although, many issues remain debated.

METHODS

A group of Italian medical and radiation oncologists with expertise in managing patients with ES-SCLC developed a list of statements divided in six areas of interest. The Delphi method was used to assess the consensus on the defined list of statements.

RESULTS

32 statements were included in the final list to be voted by the Delphi panel, and 26 reached a consensus on the agreement. A prompt involvement of a multidisciplinary team is a priority to provide an integrated treatment strategy. First-line recommended treatment is immunotherapy in combination with platinum-based chemotherapy and etoposide for four cycles followed by maintenance immunotherapy.

CONCLUSIONS

While awaiting new data from clinical trials and real-world studies, these recommendations can represent a useful tool to guide the management of ES-SCLC patients in daily practice.

The dynamic duo: A narrative review on the synergy between stereotactic body radiotherapy and immunotherapy in lung cancer treatment (Review)

Immunotherapy, particularly immune checkpoint inhibitors (ICIs), is undoubtedly one of the major breakthroughs in lung cancer research. Patient survival and prognosis have all been improved as a result, although numerous patients do not respond to immunotherapy due to various immune escape mechanisms of the tumor cells. Recent preclinical and clinical evidence has shown that stereotactic body radiotherapy (SBRT), also known as stereotactic ablative radiotherapy, has a prominent immune priming effect that could elicit antitumor immunity against specific tumor antigens and destroy distant tumor cells, thereby achieving the elusive abscopal effect, with the resulting immuno‑active tumor environment also being more conducive to ICIs. Some landmark trials have already demonstrated the survival benefit of the dynamic duo of SBRT plus immunotherapy in metastatic non‑small‑cell lung cancer, while others such as PEMBRO‑RT further suggest that the addition of SBRT to immunotherapy could expand the current indication to those who have historically responded poorly to ICIs. In the present review, the biological mechanisms that drive the synergistic effect of SBRT and immunotherapy were first briefly outlined; then, the current understanding from clinical trials was summarized and new insight into the evolving role of immunotherapy and SBRT synergy in lung cancer treatment was provided. Finally, novel avenues for discovery were highlighted. The innovation of the present review lies in the inclusion of non‑ICI immunotherapy in the discussion, which provides a more comprehensive view on the current development and future trend of SBRT + immunotherapy synergy.

Sparing the Hippocampus in Prophylactic Cranial Irradiation Using Three Different Linear Accelerators: A Comparative Study

Hippocampus protection, as an organ at risk in brain radiotherapy, might protect patients' quality of life. Prophylactic cranial irradiation (PCI) has been used traditionally in small cell lung cancer (SCLC) patients as it increases survival. This study aimed to discover the contributing parameters for a successful PCI with simultaneous protection of the hippocampus by using three different treatment machines. For this purpose, treatment plans were generated for 45 SCLC patients using three half-arcs in three linear accelerators (LINACs; Elekta Infinity, Synergy, and Axesse; Elekta Ltd, Stockholm, Sweden) with different radiation field sizes and multileaf collimator (MLC) leaf thickness characteristics. The prescribed dose was 25 Gy in 10 fractions. Thresholds for the hippocampus were calculated based on the Radiation Therapy Oncology Group 0933 dose constraints. The planning and treatment system templates were common to all three LINACs. Plan evaluation was based on the dosimetric target coverage by the 95% isodose, the maximum dose of the plan, the conformity index (CI), the degree of plan modulation (MOD), and the patient-specific quality assurance (QA) pass rate. The mean target coverage was highest for Infinity (97.3%), followed by Axesse (96.6%) and Synergy (95.5%). The mean maximum dose was higher for Synergy (27.5 Gy), followed by Infinity (27.0 Gy) and Axesse (26.9 Gy). Axesse plans had the highest CI (0.93), followed by Infinity (0.91) and Synergy (0.88). Plan MOD was lower for Synergy (2.88) compared with Infinity (3.07) and Axesse (3.69). Finally, patient-specific QA was successful in all Infinity plans, in all but one Synergy plan, and in 17/45 Axesse plans, as was expected from the field size in that treatment unit. Based on overall performance, the most favorable combination of target coverage, hippocampus sparing, and plan deliverability was obtained with the LINAC, which has the largest field opening and thinnest MLC leaves.

The Dose/Fractionation Debate in Limited-Stage Small Cell Lung Cancer

To explore the most suitable dosage regimen for limited-stage small cell lung cancer (LS-SCLC) and provide references for clinical selection, strict inclusion criteria were applied, and studies were screened from Pubmed, Embase, and Web of Science. Subsequently, data on two-year overall survival rates and dosage regimens were collected, and scatter plots were constructed to provide a comprehensive perspective. The survival benefits of various dosage regimens were evaluated, and a linear quadratic equation was utilized to fit the relationship between the biologically effective dose (BED10) and the two-year overall survival rate. Among the five randomized controlled trials, the two-year overall survival rate of ConvTRT regimens with BED10 > 60 Gy (rough value) was only at or below the median of all ConvTRT regimens or all included study regimens, indicating that increasing the number and total dose of ConvTRT does not necessarily lead to better prognosis. In the exploration of HypoTRT regimens, there was a linear positive correlation between BED10 and the two-year overall survival rate (p < 0.0001), while the exploration of HyperTRT regimens was relatively limited, with the majority focused on the 45 Gy/30 F regimen. However, the current 45 Gy/30 F regimen is not sufficient to control LS-SCLC, resulting in a high local recurrence rate. High-dose ConvTRT regimens have long treatment durations and may induce tumor regrowth which may cause reduced efficacy. Under reasonable toxicity reactions, HyperTRT or HypoTRT with higher radiotherapy doses is recommended for treating LS-SCLC.

PROTAC EZH2 degrader-1 overcomes the resistance of podophyllotoxin derivatives in refractory small cell lung cancer with leptomeningeal metastasis

BACKGROUND

Leptomeningeal metastasis (LM) of small cell lung cancer (SCLC) is a highly detrimental occurrence associated with severe neurological disorders, lacking effective treatment currently. Proteolysis-targeting chimeric molecules (PROTACs) may provide new therapeutic avenues for treatment of podophyllotoxin derivatives-resistant SCLC with LM, warranting further exploration.

METHODS

The SCLC cell line H128 expressing luciferase were mutated by MNNG to generate H128-Mut cell line. After subcutaneous inoculation of H128-Mut into nude mice, H128-LM and H128-BPM (brain parenchymal metastasis) cell lines were primarily cultured from LM and BPM tissues individually, and employed to in vitro drug testing. The SCLC-LM mouse model was established by inoculating H128-LM into nude mice via carotid artery and subjected to in vivo drug testing. RNA-seq and immunoblotting were conducted to uncover the molecular targets for LM.

RESULTS

The SCLC-LM mouse model was successfully established, confirmed by in vivo live imaging and histological examination. The upregulated genes included EZH2, SLC44A4, VEGFA, etc. in both BPM and LM cells, while SLC44A4 was particularly upregulated in LM cells. When combined with PROTAC EZH2 degrader-1, the drug sensitivity of cisplatin, etoposide (VP16), and teniposide (VM26) for H128-LM was significantly increased in vitro. The in vivo drug trials with SCLC-LM mouse model demonstrated that PROTAC EZH2 degrader-1 plus VM26 or cisplatin/ VP16 inhibited H128-LM tumour significantly compared to VM26 or cisplatin/ VP16 alone (P < 0.01).

CONCLUSION

The SCLC-LM model effectively simulates the pathophysiological process of SCLC metastasis to the leptomeninges. PROTAC EZH2 degrader-1 overcomes chemoresistance in SCLC, suggesting its potential therapeutic value for SCLC LM.

Intrathoracic Progression Is Still the Most Dominant Failure Pattern after First-Line Chemo-immunotherapy in Extensive-Stage Small-Cell Lung Cancer: Implications for Thoracic Radiotherapy

PURPOSE

This study aimed to compare the failure patterns before and after the introduction of immunotherapy and to determine the role of thoracic radiotherapy (TRT) in extensive-stage small-cell lung cancer (ES-SCLC) treatment.

MATERIALS AND METHODS

We retrospectively reviewed 294 patients with ES-SCLC, of which 62.2% underwent chemotherapy alone, 13.3% underwent chemotherapy followed by consolidative TRT (TRT group), and 24.5% underwent chemotherapy with immune checkpoint inhibitor (ICI group). We performed propensity-score matching (PSM) to compare each treatment group.

RESULTS

The median follow-up duration was 10.4 months. At the first relapse, in the cohort showing objective response, the proportion of cases showing intrathoracic progression was significantly lower in the TRT group (37.8%) than in the chemotherapy-alone (77.2%, p < 0.001) and the ICI (60.3%, p=0.03) groups. Furthermore, in the subgroup analysis, TRT showed benefits related to intrathoracic progression-free survival (PFS) in comparison with ICI in patients with less than two involved extrathoracic sites (p=0.008) or without liver metastasis (p=0.02) or pleural metastasis (p=0.005) at diagnosis. After PSM, the TRT group showed significantly better intrathoracic PFS than both chemotherapy-alone and ICI groups (p < 0.001 and p=0.04, respectively), but showed no significant benefit in terms of PFS and overall survival in comparison with the ICI group (p=0.17 and p=0.31, respectively).

CONCLUSION

In ES-SCLC, intrathoracic progression was the most dominant failure pattern after immunotherapy. In the era of chemoimmunotherapy, consolidative TRT can still be considered a useful treatment strategy for locoregional control.

Sterotactic Ablative Radiotherapy in a Multicentric Series of Oligometastatic SCLC: The SAMOS Cohort

AIMS

SCLC is the most aggressive lung cancer histology with a 5-year OS <10%. At the diagnosis, almost two-thirds of the SCLC an Extended Disease presentation. Two randomized studies (CASPIAN and ImPower133) demonstrated an OS improvement, when immunotherapy was prescribed as maintenance therapy after standard chemotherapy. To date, SABR has had a limited indication in managing metastatic SCLC, although recent reports proposed it as a valid treatment option in selected patients. We propose a retrospective multicentric analysis of patients treated with SABR for oligometastatic SCLC.

METHOD

Data of patients affected by oligometastatic-SCLC treated with SABR between 2017 and 2022 in 11 Italian centers were collected. Clinical and therapeutic variables together with OS and time to next treatment were analyzed. Univariate analysis with Kaplan-Meier curve were calculated, and log-rank test were applied. Cox proportional hazard model was used for multivariate analysis.

RESULTS

Data from 93 patients and 132 metastatic lesions were analyzed. The median age was 64 years (36-86) and all but 1 had Performance Status 0 or 1. Fifty-two patients presented ED at diagnosis. The first line treatment was radiochemotherapy in 42%, CHT alone in 24% and CHT-IO in 28%, others treatment accounts for 4% and only 2% of patients underwent best supportive care. Of the 132 lesions treated with SBRT 55 were in brain, 27 in lung, 11 in liver, 10 in lymph nodes, 8 in bones and 20 in adrenal gland. Median OS was 14 months, 1 year-OS and 2 years OS were 53% and 27%, respectively. The median TtNT was 14 months for the entire population. Of all the analyzed variables only, the anatomical site of the metastases and their number showed statistical significance in the univariate analysist, confirmed in the subsequent multivariate.

CONCLUSION

SABR seems to play a role in delaying further systemic lines in oligometastatic disease and to extend the use of ongoing treatment in oligoprogressive state. Prospective studies are needed to confirm these findings.

Efficacy and safety of thoracic radiotherapy in extensive-stage small-cell lung cancer patients receiving first-line immunotherapy plus chemotherapy: a propensity score matched multicentre retrospective analysis

BACKGROUND

Platinum-etoposide chemotherapy combined with immune checkpoint inhibitors (ICIs) has been recommended as the first-line standard treatment for extensive-stage small-cell lung cancer (ES-SCLC). However, the effect of thoracic radiotherapy (TRT) on these patients is still unknown. This study aimed to evaluate the efficacy and safety of TRT for ES-SCLC patients who responded to first-line ICIs and chemotherapy (CHT).

METHODS

Patients who received 4 to 6 cycles of ICIs and CHT as first-line therapy at three hospitals between 2018 and 2022 were included in the analysis. All patients were divided into two groups based on whether they received TRT as first-line treatment, and propensity score matching (PSM) was performed to ensure that the characteristics of two groups were well-balanced. The primary endpoints were overall survival (OS) and progression-free survival (PFS), and the secondary endpoint was toxic effects.

RESULTS

A total of 276 patients were included, and the median follow-up time was 22.3 (range, 4.0-53.73) months. After PSM, 197 patients were further analysed, and 99 of whom received TRT. The baseline characteristics were well-balanced between patients in the TRT and non-TRT groups. There were significant differences in PFS between the TRT and non-TRT groups, with the median PFS of 10.76 and 7.63 months, respectively (P = 0.014). Significantly improved OS was observed in the TRT group (21.67 vs. 16.6 months, P = 0.009). In addition, the use of TRT was an independent prognostic factor for PFS and OS of ES-SCLC patients receiving ICIs plus CHT. In terms of safety, no significant increase of any grades adverse event (AE) (P = 0.874) and G3-4 AE (P = 0.909) was observed for patients receiving TRT. Radiation esophagitis, gastrointestinal and hematologic toxicities were the most common AEs in TRT group, which were tolerable. And high-dose radiotherapy was associated with higher incidence of pneumonitis.

CONCLUSION

Addition of TRT showed significant survival benefits and well tolerability in ES-SCLC patients receiving platinum-etoposide CHT and ICIs, which could be a feasible first-line treatment strategy for ES-SCLC patients.

Effectiveness of CT radiomic features combined with clinical factors in predicting prognosis in patients with limited-stage small cell lung cancer

BACKGROUND

The prognosis of SCLC is poor and difficult to predict. The aim of this study was to explore whether a model based on radiomics and clinical features could predict the prognosis of patients with limited-stage small cell lung cancer (LS-SCLC).

METHODS

Simulated positioning CT images and clinical features were retrospectively collected from 200 patients with histological diagnosis of LS-SCLC admitted between 2013 and 2021, which were randomly divided into the training (n = 140) and testing (n = 60) groups. Radiomics features were extracted from simulated positioning CT images, and the t-test and the least absolute shrinkage and selection operator (LASSO) were used to screen radiomics features. We then constructed radiomic score (RadScore) based on the filtered radiomics features. Clinical factors were analyzed using the Kaplan-Meier method. The Cox proportional hazards model was used for further analyses of possible prognostic features and clinical factors to build three models including a radiomic model, a clinical model, and a combined model including clinical factors and RadScore. When a model has prognostic predictive value (AUC > 0.7) in both train and test groups, a nomogram will be created. The performance of three models was evaluated using area under the receiver operating characteristic curve (AUC) and Kaplan-Meier analysis.

RESULTS

A total of 1037 features were extracted from simulated positioning CT images which were contrast enhanced CT of the chest. The combined model showed the best prediction, with very poor AUC for the radiomic model and the clinical model. The combined model of OS included 4 clinical features and RadScore, with AUCs of 0.71 and 0.70 in the training and test groups. The combined model of PFS included 4 clinical features and RadScore, with AUCs of 0.72 and 0.71 in the training and test groups. T stages, ProGRP and smoke status were the independent variables for OS in the combined model, whereas T stages, ProGRP and prophylactic cranial irradiation (PCI) were the independent factors for PFS. There was a statistically significant difference between the low- and high-risk groups in the combined model of OS (training group, p < 0.0001; testing group, p = 0.0269) and PFS (training group, p < 0.0001; testing group, p < 0.0001).

CONCLUSION

Combined models involved RadScore and clinical factors can predict prognosis in LS-SCLC and show better performance than individual radiomics and clinical models.

Radiotherapy in the management of synchronous metastatic lung cancer

Metastatic lung cancer classically portends a poor prognosis. The management of metastatic lung cancer has dramatically changed with the emergence of immune checkpoint inhibitors, targeted therapy and due to a better understanding of the oligometastatic process. In metastatic lung cancers, radiation therapy which was only used with palliative intent for decades, represents today a promising way to treat primary and oligometastatic sites with a curative intent. Herein we present through a literature review the role of radiotherapy in the management of synchronous metastatic lung cancers.

Real-world impact of the introduction of chemo-immunotherapy in extended small cell lung cancer: a multicentric analysis

Background

Recent clinical trials demonstrated longer survival in extended small cell lung cancer (SCLC) patients treated with immunotherapy in addition to chemotherapy. However, the magnitude of benefit is modest and the impact in real-world setting has to be fully established.

Methods

We collected clinical data and radiological imaging of patients affected by extended or relapsing SCLC and consecutively treated according to clinical practice between 2016 and 2023. As primary end-point, we compared pre-defined outcome indicators before and after the introduction of chemo-immunotherapy (May 2020): 6-month and 12-month progression free survival (PFS) rate, 12-month and 18-month overall survival (OS). Among those who were treated after May 2020, patients who did not receive immunotherapy according to treating physician's choice were included in the analysis to minimize clinical selection bias.

Results

The analysis included 214 patients: 132 (61.7%) were treated in an Academic cancer center and 82 (38.3%) in two community hospitals; 104 were treated before May 2020. Median PFS of the overall study population was 4.8 months (95% confidence interval [95% CI]: 4.4-5.4), median OS was 7.1 months (95% CI: 6.3-7.7). Estimated PFS and OS were significantly longer in patients treated after May 2020 with hazard ratio (HR) for PFS and OS of 0.61 (95% CI: 0.46-0.81, p < 0.001) and 0.70 (95% CI: 0.52-0.93, p = 0.015), respectively. 6-month PFS rate increased from 27% to 40% (p = 0.04) while 12-months PFS raised from 1% to 11% (p = 0.003). 12-month and 18-month OS rate increased from 15% to 28% (p = 0.03) and from 2.1% to 12% (p = 0.009), respectively. After May 2020 the median number of hospitalization days per patient decreased significantly and the incidence of severe AEs was similar. Among patients treated with chemo-immunotherapy, the onset of immune-related AEs was associated with improved PFS and OS (HR 0.55, 95% CI: 0.35-0.89, p = 0.012 and HR 0.47, 95%CI 0.28-0.77, p = 0.002, respectively).

Conclusions

The real-world analysis shows a meaningful improvement of outcome indicators after the introduction of chemo-immunotherapy, with reduction of the duration of hospitalization, thus supporting the use of chemo-immunotherapy and the need for further biomarker research.

Consolidative thoracic radiation therapy for extensive-stage small cell lung cancer in the era of first-line chemoimmunotherapy: preclinical data and a retrospective study in Southern Italy

Background

Consolidative thoracic radiotherapy (TRT) has been commonly used in the management of extensive-stage small cell lung cancer (ES-SCLC). Nevertheless, phase III trials exploring first-line chemoimmunotherapy have excluded this treatment approach. However, there is a strong biological rationale to support the use of radiotherapy (RT) as a boost to sustain anti-tumor immune responses. Currently, the benefit of TRT after chemoimmunotherapy remains unclear. The present report describes the real-world experiences of 120 patients with ES-SCLC treated with different chemoimmunotherapy combinations. Preclinical data supporting the hypothesis of anti-tumor immune responses induced by RT are also presented.

Methods

A total of 120 ES-SCLC patients treated with chemoimmunotherapy since 2019 in the South of Italy were retrospectively analyzed. None of the patients included in the analysis experienced disease progression after undergoing first-line chemoimmunotherapy. Of these, 59 patients underwent TRT after a multidisciplinary decision by the treatment team. Patient characteristics, chemoimmunotherapy schedule, and timing of TRT onset were assessed. Safety served as the primary endpoint, while efficacy measured in terms of overall survival (OS) and progression-free survival (PFS) was used as the secondary endpoint. Immune pathway activation induced by RT in SCLC cells was explored to investigate the biological rationale for combining RT and immunotherapy.

Results

Preclinical data supported the activation of innate immune pathways, including the STimulator of INterferon pathway (STING), gamma-interferon-inducible protein (IFI-16), and mitochondrial antiviral-signaling protein (MAVS) related to DNA and RNA release. Clinical data showed that TRT was associated with a good safety profile. Of the 59 patients treated with TRT, only 10% experienced radiation toxicity, while no ≥ G3 radiation-induced adverse events occurred. The median time for TRT onset after cycles of chemoimmunotherapy was 62 days. Total radiation dose and fraction dose of TRT include from 30 Gy in 10 fractions, up to definitive dose in selected patients. Consolidative TRT was associated with a significantly longer PFS than systemic therapy alone (one-year PFS of 61% vs. 31%, p<0.001), with a trend toward improved OS (one-year OS of 80% vs. 61%, p=0.027).

Conclusion

Multi-center data from establishments in the South of Italy provide a general confidence in using TRT as a consolidative strategy after chemoimmunotherapy. Considering the limits of a restrospective analysis, these preliminary results support the feasibility of the approach and encourage a prospective evaluation.

Re-examining prophylactic cranial irradiation in small cell lung cancer: a systematic review and meta-analysis

Background

Patients with small cell lung cancer (SCLC) are at high risk for brain metastases. Prophylactic cranial irradiation (PCI) is recommended in this population to reduce the incidence of brain metastases and prolong survival. We aimed to assesses the efficacy of PCI in this population in the era of routine brain imaging. To our knowledge, this is the first systematic review and meta-analysis to examine the use among patients who were radiographically confirmed not to have brain metastases after completion of first-line therapy.

Methods

In this systematic review and meta-analysis, cohort studies and controlled trials reporting on the use of PCI for patients SCLC were identified in EMBASE, MEDLINE, CENTRAL, and grey literature sources. The literature search was conducted on November 12, 2023. Summary data were extracted. Random-effects meta-analyses pooled hazard ratios (HR) for the primary outcome of overall survival between PCI and no intervention groups. This study is registered with the Open Science Framework, DOI:10.17605/OSF.IO/BC359, and PROSPERO, CRD42021249466.

Findings

Of 4318 identified records, 223 were eligible for inclusion. 109 reported on overall survival in formats amenable to meta-analysis; PCI was associated with longer survival in all patients with SCLC (HR 0.59; 95% CI, 0.55-0.63; p < 0.001; n = 56,770 patients), patients with limited stage disease (HR 0.60; 95% CI, 0.55-0.65; p < 0.001; n = 78 studies; n = 27,137 patients), and patients with extensive stage disease (HR 0.59; 95% CI, 0.51-0.70; p < 0.001; n = 28 studies; n = 26,467 patients). Between-study heterogeneity was significant when pooled amongst all studies (I2 = 73.6%; 95% CI 68.4%-77.9%). Subgroup analysis did not reveal sources of heterogeneity. In a subgroup analysis on studies that used magnetic resonance imaging to exclude presence of brain metastases at restaging among all patients, overall survival did not differ significantly between patients who did or did not receive PCI (HR 0.74; 95% CI, 0.52-1.05; p = 0.08; n = 9 studies; n = 1384 patients).

Interpretation

Our findings suggested that administration of PCI is associated with a survival benefit, but not when considering studies that radiographically confirmed absence of brain metastases, suggesting that the survival benefit conferred by PCI might be therapeutic rather than prophylactic.

Funding

No funding.

Systemic Therapy for Small-Cell Lung Cancer: ASCO-Ontario Health (Cancer Care Ontario) Guideline

PURPOSE

To provide evidence-based recommendations to practicing clinicians on the management of patients with small-cell lung cancer.

METHODS

An Expert Panel of medical oncology, thoracic surgery, radiation oncology, pulmonary, community oncology, research methodology, and advocacy experts were convened to conduct a literature search, which included systematic reviews, meta-analyses, and randomized controlled trials published from 1990 through 2022. Outcomes of interest included response rates, overall survival, disease-free survival or recurrence-free survival, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.

RESULTS

The literature search identified 95 relevant studies to inform the evidence base for this guideline.

RECOMMENDATIONS

Evidence-based recommendations were developed to address systemic therapy options, timing of therapy, treatment in patients who are older or with poor performance status, role of biomarkers, and use of myeloid-supporting agents in patients with small-cell lung cancer.Additional information is available at www.asco.org/thoracic-cancer-guidelines.

The Era of Immunotherapy in Small-Cell Lung Cancer: More Shadows Than Light?

Small-cell lung cancer is an extremely chemo-sensitive disease; the addition of immunotherapy to chemotherapy has demonstrated a slight clinical benefit in pivotal trials, even with a statistically significant difference in terms of survival outcomes when compared to chemotherapy alone. In this scenario, the role of radiotherapy as a consolidation treatment in thoracic disease or as a prophylactic therapy in the brain should be clarified. In addition, due to the frailty and the poor prognostic characteristics of these patients, the need for predictive biomarkers that could support the use of immunotherapy is crucial. PD-L1 and TMB are not actually considered definitive biomarkers due to the heterogeneity of results in the literature. A new molecular classification of small-cell lung cancer based on the expression of key transcription factors seems to clarify the disease behavior, but the knowledge of this molecular subtype is still insufficient and the application in clinical practice far from reality; this classification could lead to a better understanding of SCLC disease and could provide the right direction for more personalized treatment. The aim of this review is to investigate the current knowledge in this field, evaluating whether there are predictive biomarkers and clinical patient characteristics that could help us to identify those patients who are more likely to respond to immunotherapy.

Real-world predictors of survival in patients with limited-stage small-cell lung cancer in Manitoba, Canada

Background

Although therapy for limited-stage small-cell lung cancer (LS-SCLC) is administered with curative intent, most patients relapse and eventually die of recurrent disease. Chemotherapy (CT) with concurrent radiotherapy (RT) remains the standard of care for LS-SCLC; however, this could evolve in the near future. Therefore, understanding the current prognostic factors associated with survival is essential.

Objective

This real-world analysis examines factors associated with long-term survival in patients with LS-SCLC treated with CT in Manitoba, Canada.

Methods

A retrospective cohort study was conducted using Manitoba Cancer Registry and CancerCare Manitoba records. Eligible patients were aged >18 years and had cytologically confirmed LS-SCLC diagnosed between January 1, 2004, and December 31, 2018, for which they received CT ± RT. Baseline patient, disease, and treatment characteristics and survival duration, characterized as short (<6 months), medium (6-24 months), and long term (>24 months), were extracted. Overall survival (OS) was estimated at one, two, and five years and assessed using Kaplan-Meier methods and Cox proportional hazards models.

Results

Over the 15-year study period, 304 patients met the eligibility criteria. Long-term survivors comprised 39.1% of the cohort; at diagnosis, this subgroup was younger, more likely to have Eastern Cooperative Oncology Group Performance Status (ECOG PS) 0, and have normal lactate dehydrogenase, sodium, and hemoglobin levels. OS estimates for the entire cohort at one, two, and five years were 66%, 38%, and 18%, respectively. In the ECOG PS 0 subgroup, OS estimates at one, two, and five years were 85%, 52%, and 24%, respectively; OS estimates were 60%, 35%, and 17%, respectively, for ECOG PS 1-2 and were 47%, 23%, and 10%, respectively, for ECOG PS 3-4. OS was significantly higher among patients with normal serum sodium and hemoglobin levels than those with abnormal levels. Univariable hazard regression models found that ECOG PS, age at diagnosis, receipt of prophylactic cranial irradiation (PCI), and thoracic RT were associated with survival. On multivariable hazard regression, ECOG PS and receipt of PCI were associated with survival.

Conclusion

Survival for greater than two years in patients with LS-SCLC treated with CT ± RT was associated with ECOG PS and receipt of PCI.

The Impact of Prophylactic Cranial Irradiation and Consolidative Thoracic Radiation Therapy for Extensive Stage Small-Cell Lung Cancer in the Transition to the Chemo-Immunotherapy Era: A Single Institution Series

INTRODUCTION

Extensive-stage small-cell lung cancer (ES-SCLC) continues to have poor survival due to its aggressive behavior, despite improvements with incorporation of immunotherapy with standard chemotherapy. Controversy exists regarding the role of consolidative thoracic radiation therapy (TRT) and prophylactic cranial irradiation (PCI) in ES-SCLC due to high recurrence rates. We report our institutional result of the benefit of PCI and TRT in ES-SCLC.

METHODS

Patients with ES-SCLC without intracranial metastasis at diagnosis (N = 163) were included. All patients completed systemic therapy with or without immunotherapy based on time of standard of care. Cohorts were divided by systemic therapy use and further subdivided by treatment with PCI and TRT. Overall survival (OS) and progression-free survival (PFS) were estimated by the Kaplan-Meier method with log-rank test for comparison. The effects of TRT and PCI were estimated by multivariable (MVA) Cox regression.

RESULTS

Seventy-four patients (45.4%) received TRT, and 33.1% (n = 54) received PCI. The median follow-up was 11 months (3-85 months). PCI improved median OS to 15 months from 10 months, P = .02) and median PFS to 8.5 months from 5 months (P = .02) which remained significant on MVA, P = .02 and P = .02, respectively. TRT improved OS on UVA (P = 0.002) but was not significant on MVA. TRT did not improve PFS.

CONCLUSION

This study including chemotherapy and chemo-immunotherapy suggests improved outcomes with addition of PCI in patients with ES-SCLC while TRT did not show benefit to either OS or PFS. A future trial is needed to evaluate the role of TRT and PCI in the era of chemo-immunotherapy.

Reduction of tumor volume during radiotherapy in patients with small-cell lung cancer and its prognostic significance

BACKGROUND

Several studies have reported the potential prognostic significance of tumor volume reduction ratio (VRR) induced by radiotherapy (RT) in patients with non-small-cell lung cancer. However, there are no data yet on the prognostic significance of volumetric shrinkage in patients with small-cell lung cancer (SCLC). This study aimed to demonstrate the correlation between tumor volume reduction ratio and treatment outcomes.

MATERIALS AND METHODS

The study included 61 patients with SCLC treated with fractionated RT of the primary tumor at our institution between 2013 and 2020. The relationship between volumetric changes in gross tumor volume (GTV) during radiotherapy and outcomes were analyzed and reported.

RESULTS

The median radiation dose was 59.4 Gy (median fraction dose was 1.8 Gy). The median GTV before radiotherapy was 74 cm3, with a median GTV reduction of 48%. There was a higher VRR in patients receiving concurrent radiochemotherapy (p = 0.05). No volumetric parameters were identified as relevant predictors of outcome in the entire cohort. In multivariate analysis, only age had an impact on survival, while prophylactic whole-brain radiation influenced the progression-free survival significantly.

CONCLUSION

Concurrent chemotherapy was associated with a higher VRR than sequential chemotherapy. No significant impact of VRR on patients' outcome or survival was detected.

Prospective Evaluation of Limited-Stage Small Cell Lung Cancer Radiotherapy Fractionation Regimen Usage and Acute Toxicity in a Large Statewide Quality Collaborative

PURPOSE

National guidelines on limited-stage small cell lung cancer (LS-SCLC) treatment give preference to a hyperfractionated regimen of 45 Gy in 30 fractions delivered twice daily; however, use of this regimen is uncommon compared with once-daily regimens. The purpose of this study was to characterize the LS-SCLC fractionation regimens used throughout a statewide collaborative, analyze patient and treatment factors associated with these regimens, and describe real-world acute toxicity profiles of once- and twice-daily radiation therapy (RT) regimens.

METHODS AND MATERIALS

Demographic, clinical, and treatment data along with physician-assessed toxicity and patient-reported outcomes were prospectively collected by 29 institutions within the Michigan Radiation Oncology Quality Consortium between 2012 and 2021 for patients with LS-SCLC. We modeled the influence of RT fractionation and other patient-level variables clustered by treatment site on the odds of a treatment break specifically due to toxicity with multilevel logistic regression. National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0, incident grade 2 or worse toxicity was longitudinally compared between regimens.

RESULTS

There were 78 patients (15.6% overall) treated with twice-daily RT and 421 patients treated with once-daily RT. Patients receiving twice-daily RT were more likely to be married or living with someone (65% vs 51%; P = .019) and to have no major comorbidities (24% vs 10%; P = .017). Once-daily RT fractionation toxicity peaked during RT, and twice-daily toxicity peaked within 1 month after RT. After stratifying by treatment site and adjusting for patient-level variables, once-daily treated patients had 4.11 (95% confidence interval, 1.31-12.87) higher odds of treatment break specifically due to toxicity than twice-daily treated patients.

CONCLUSIONS

Hyperfractionation for LS-SCLC remains infrequently prescribed despite the lack of evidence demonstrating superior efficacy or lower toxicity of once-daily RT. With peak acute toxicity after RT and lower likelihood of a treatment break with twice-daily fractionation in real-word practice, providers may start using hyperfractionated RT more frequently.

Consensus Quality Measures and Dose Constraints for Lung Cancer From the Veterans Affairs Radiation Oncology Quality Surveillance Program and ASTRO Expert Panel

PURPOSE

For patients with lung cancer, it is critical to provide evidence-based radiation therapy to ensure high-quality care. The US Department of Veterans Affairs (VA) National Radiation Oncology Program partnered with the American Society for Radiation Oncology (ASTRO) as part of the VA Radiation Oncology Quality Surveillance to develop lung cancer quality metrics and assess quality of care as a pilot program in 2016. This article presents recently updated consensus quality measures and dose-volume histogram (DVH) constraints.

METHODS AND MATERIALS

A series of measures and performance standards were reviewed and developed by a Blue-Ribbon Panel of lung cancer experts in conjunction with ASTRO in 2022. As part of this initiative, quality, surveillance, and aspirational metrics were developed for (1) initial consultation and workup; (2) simulation, treatment planning, and treatment delivery; and (3) follow-up. The DVH metrics for target and organ-at-risk treatment planning dose constraints were also reviewed and defined.

RESULTS

Altogether, a total of 19 lung cancer quality metrics were developed. There were 121 DVH constraints developed for various fractionation regimens, including ultrahypofractionated (1, 3, 4, or 5 fractions), hypofractionated (10 and 15 fractionations), and conventional fractionation (30-35 fractions).

CONCLUSIONS

The devised measures will be implemented for quality surveillance for veterans both inside and outside of the VA system and will provide a resource for lung cancer-specific quality metrics. The recommended DVH constraints serve as a unique, comprehensive resource for evidence- and expert consensus-based constraints across multiple fractionation schemas.

Feasibility and long-term outcomes of post-chemotherapy-based consolidation radiotherapy in extensive stage small-cell lung cancer

Background

The target definition of consolidation radiotherapy (RT) for extensive stage small-cell lung cancer (ES-SCLC) has not been standardized. This study aimed to demonstrate the feasibility of post-chemotherapy based consolidation RT in ES-SCLC.

Methods

All ES-SCLC patients without initial brain metastases who completed ≥ 4 cycles of systemic therapy at Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University from 2012 to 2021 were included in this retrospective study. We correlated the site of first recurrence to the post-chemotherapy-based radiation volume (small-field). Relapse pattern, progression-free survival (PFS) and overall survival (OS) were compared between those received and did not receive consolidation RT.

Results

A total of 152 patients were followed up for a median of 31.7 months (interquartile range [IQR], 23.9-39.6 months). The median PFS and OS of the cohort were 8.3 months (IQR, 6.1-11.2 months) and 16.2 months (IQR, 9.9-24.9 months), respectively. Thoracic consolidation RT served not only as an independent prognostic factor for improved PFS in the entire cohort, but also significantly prolonged OS in the subgroup without synchronous liver metastases. Small-field consolidation RT markedly reduced in-field recurrences (hazard ratio [HR], 0.28 [95% CI, 0.12-0.38]; P < 0.001) without increasing out-of-field recurrences (HR, 0.40 [95% CI, 0.13-1.16]; P = 0.080). No relapse was observed at the margin of the targets. Treatment-related toxicities were moderate, with grade 3 acute radiation pneumonia, radiation esophagitis, and bone marrow suppression rates of 8.3%, 3.1%, and 12.5%, respectively. No grade 5 toxicity occurred.

Conclusion

Small-field consolidation RT based on post-chemotherapy volume is safe and can significantly improve local control in ES-SCLC.

Radiotherapy for extensive-stage small-cell lung cancer in the immunotherapy era

Currently, chemoimmunotherapy is the first-line treatment for extensive-stage small-cell lung cancer (ES-SCLC). However, only 0.8%-2.5% of the patients presented complete response after chemoimmunotherapy. Considering that ES-SCLC is highly sensitive to radiotherapy, the addition of radiotherapy after first-line treatment for ES-SCLC could further improve local control, which may be beneficial for patients' survival. Prior studies have shown that consolidative thoracic radiotherapy (cTRT) can decrease disease progression and improve overall survival in patients with ES-SCLC who respond well to chemotherapy. However, the efficacy and safety of cTRT in the immunotherapy era remain unclear owing to a lack of prospective studies. Prophylactic cranial irradiation (PCI) has been shown to decrease brain metastasis (BM) and prolong survival in patients with limited-stage SCLC in previous reports. However, according to current guidelines, PCI is not commonly recommended for ES-SCLC. Immunotherapy has the potential to reduce the incidence of BM. Whether PCI can be replaced with regular magnetic resonance imaging surveillance for ES-SCLC in the era of immunotherapy remains controversial. Whole brain radiation therapy (WBRT) is the standard treatment for BM in SCLC patients. Stereotactic radiosurgery (SRS) has shown promise in the treatment of limited BM. Considering the potential of immunotherapy to decrease BM, it is controversial whether SRS can replace WBRT for limited BM in the immunotherapy era. Additionally, with the addition of immunotherapy, the role of palliative radiotherapy may be weakened in patients with asymptomatic metastatic lesions. However, it is still indispensable and urgent for patients with obvious symptoms of metastatic disease, such as spinal cord compression, superior vena cava syndrome, lobar obstruction, and weight-bearing metastases, which may critically damage the quality of life and prognosis. To improve the outcome of ES-SCLC, we discuss the feasibility of radiotherapy, including cTRT, PCI, WBRT/SRS, and palliative radiotherapy with immunotherapy based on existing evidence, which may offer specific prospects for further randomized trials and clinical applications.

The role of thoracic consolidative radiotherapy in the setting of immunotherapy in extensive stage small cell lung cancer

The improvement in treatment strategies and outcomes in small cell lung cancer (SCLC) has lagged behind other cancers. The addition of immune checkpoint inhibitors (ICIs), durvalumab and atezolizumab, to the platinum-based chemotherapy in frontline setting has improved the survival in extensive stage SCLC, (ES-SCLC), albeit modestly, and is now the new standard of care. Prior to advent of immunotherapy into the therapeutic armamentarium in ES-SCLC, consolidative thoracic radiotherapy (TRT) was associated with improved thoracic control and survival outcomes. In the era of ICIs, the role of TRT is not well defined, chiefly because TRT was not incorporated in any immunotherapy trials, secondly due to concerns regarding the increased risks of pneumonitis, and finally uncertain magnitude of benefit with this combined approach. In principle, radiation can increase in the immunogenicity of tumor and hence the activity of immune checkpoint blockade, thereby increasing efficacy both locally and distantly. Such an approach has been promising in non-small cell lung cancer with ICIs improving outcomes after concurrent chemoradiation, but remains unanswered in ES-SCLC. It is, thus, possible that the modest improvement in survival by addition of ICIs to chemotherapy in ES-SCLC can be further improved by the incorporation of consolidative TRT in selected patients. Several early phase trials and retrospective studies have suggested that such an approach may be feasible and safe. Prospective trials are ongoing to answer whether adding radiation therapy to chemoimmunotherapy will improve outcomes in ES-SCLC.

Patterns of care for people with small cell lung cancer in Victoria, 2011-19: a retrospective, population-based registry data study

OBJECTIVES

To report stage-specific patterns of treatment and the influence of management and treatment type on survival rates for people newly diagnosed with small cell lung cancer (SCLC).

DESIGN

Cross-sectional patterns of care study; analysis of data prospectively collected for the Victorian Lung Cancer Registry (VLCR).

SETTING, PARTICIPANTS

All people diagnosed with SCLC in Victoria during 1 April 2011 - 18 December 2019.

MAIN OUTCOME MEASURES

Stage-specific management and treatment of people with SCLC; median survival time.

RESULTS

During 2011-19, 1006 people were diagnosed with SCLC (10.5% of all lung cancer diagnoses in Victoria); their median age was 69 years (interquartile range [IQR], 62-77 years), 429 were women (43%), and 921 were current or former smokers (92%). Clinical stage was defined for 896 people (89%; TNM stages I-III, 268 [30%]; TNM stage IV, 628 [70%]) and ECOG performance status at diagnosis for 663 (66%; 0 or 1, 489 [49%]; 2-4, 174 [17%]). The cases of 552 patients had been discussed at multidisciplinary meetings (55%), 377 people had received supportive care screening (37%), and 388 had been referred for palliative care (39%). Active treatment was received by 891 people (89%): chemotherapy, 843 (84%); radiotherapy, 460 (46%); chemotherapy and radiotherapy, 419 (42%); surgery, 23 (2%). Treatment had commenced within fourteen days of diagnosis for 632 of 875 patients (72%). Overall median survival time from diagnosis was 8.9 months (IQR, 4.2-16 months; stage I-III: 16.3 [IQR, 9.3-30] months; stage IV: 7.2 [IQR, 3.3-12] months). Multidisciplinary meeting presentation (hazard ratio [HR], 0.66; 95% CI, 0.58-0.77), multimodality treatment (HR, 0.42; 95% CI, 0.36-0.49), and chemotherapy within fourteen days of diagnosis (HR, 0.68; 95% CI, 0.48-0.94) were each associated with lower mortality during follow-up.

CONCLUSION

Rates of supportive care screening, multidisciplinary meeting evaluation, and palliative care referral for people with SCLC could be improved. A national registry of SCLC-specific management and outcomes data could improve the quality and safety of care.

Twenty-Month Regression Following Concurrent Conventional Whole-Brain Irradiation and Chemoimmunotherapy for ≥3.8 cm Cerebellar Metastasis From Small Cell Lung Cancer

Standard whole-brain radiotherapy (WBRT) alone for large brain metastases (BMs) from small cell lung cancer (SCLC) has limited efficacy and durability, and stereotactic radiosurgery (SRS) alone for symptomatic posterior fossa BMs >3 cm with satellite lesions is challenging. Herein, we describe the case of a 73-year-old female presenting with treatment-naïve SCLC and 15 symptomatic multiple BMs, including a ≥3.8-cm cerebellar mass (≥17.7 cm3) and two adjacent lesions; otherwise, the SCLC was confined to the thorax. The patient was initially treated concurrently with conventional WBRT (30 Gy in 10 fractions) without boost and chemoimmunotherapy (CIT) consisting of carboplatin, etoposide, and atezolizumab. Atezolizumab was excluded during irradiation. Five months after WBRT, the large cerebellar lesion had remarkably regressed, and the smaller lesions (≤17 mm) showed complete responses (CRs) without local progression at 20 months. However, six and 16 months after WBRT, the thoracic lesions had progressed, and although amrubicin was administered, four new BMs, including pons involvement, had developed, respectively. Despite the CRs of the four BMs following SRS (49.6 Gy in eight fractions) and the sustained regression of the thoracic lesions, meningeal dissemination and multiple new BMs were evident 3.5 months post-SRS. The small remnant of the large BM and/or newly developed BMs abutting the cerebrospinal fluid (CSF) space could have led to CSF dissemination, the presumed cause of the patient's death. Taken together, concurrent chemo-WBRT and subsequent CIT can provide excellent and durable tumor responses for SCLC BMs, but may not be fully sufficient for BMs ≥3.8 cm. Therefore, in cases with large lesions, focal dose escalation of the large lesions, consolidative thoracic radiotherapy, and dose de-escalation in the macroscopically unaffected brain region may prevent or attenuate CSF dissemination, new BM development, and adverse effects and thus should be considered.

Real-world outcomes of PD-L1 inhibitors combined with thoracic radiotherapy in the first-line treatment of extensive stage small cell lung cancer

BACKGROUND

The CREST study showed that the addition of thoracic radiotherapy (TRT) could improve the survival rate in patients with extensive stage small cell lung cancer (ES-SCLC), but whether TRT can bring survival benefit in the era of immunotherapy remains controversial. This study aimed to explore the efficacy and safety of adding TRT to the combination of PD-L1 inhibitors and chemotherapy.

METHODS

The patients who received durvalumab or atezolizumab combined with chemotherapy as the first-line treatment of ES-SCLC from January 2019 to December 2021 were enrolled. They were divided into two groups, based on whether they received TRT or not. Propensity score matching (PSM) with a 1:1 ratio was performed. The primary endpoints were progression-free survival (PFS), overall survival (OS) and safety.

RESULTS

A total of 211 patients with ES-SCLC were enrolled, of whom 70 (33.2%) patients received standard therapy plus TRT as first-line treatment, and 141 (66.8%) patients in the control group received PD-L1 inhibitors plus chemotherapy. After PSM, a total of 57 pairs of patients were enrolled in the analysis. In all patients, the median PFS (mPFS) in the TRT and non-TRT group was 9.5 and 7.2 months, respectively, with HR = 0.59 (95%CI 0.39-0.88, p = 0.009). The median OS (mOS) in the TRT group was also significantly longer than that in the non-TRT group (24.1 months vs. 18.5 months, HR = 0.53, 95%CI 0.31-0.89, p = 0.016). Multivariable analysis showed that baseline liver metastasis and the number of metastases ≥ 3 were independent prognostic factors for OS. Addition of TRT increased the incidence of treatment-related pneumonia (p = 0.018), most of which were grade 1-2.

CONCLUSIONS

Addition of TRT to durvalumab or atezolizumab plus chemotherapy significantly improves survival in ES-SCLC. Although it may leads to increased incidence of treatment-related pneumonia, a majority of the cases can be relieved after symptomatic treatment.

Efficacy of Prophylactic Cranial Irradiation According to the Risk of Extracranial Recurrence in Limited-Stage Small Cell Lung Cancer

PURPOSE

We aimed to evaluate the effectiveness of prophylactic cranial irradiation (PCI) for "early brain metastasis", which occurs before extracranial recurrence (ECR), and "late brain metastasis", which occurs after ECR, in limited-stage small cell lung cancer (LS-SCLC).

Materials and Methods

We retrospectively analyzed 271 LS-SCLC patients who underwent definitive chemoradiation. All patients were initially staged with brain magnetic resonance imaging and positron emission tomography. Intracranial recurrence (ICR), ECR, progression-free rate (PFR), and overall survival (OS) were analyzed as clinical endpoints. The competing risk of the first recurrence with ICR (ICRfirst) was evaluated. Significantly associated variables in multivariate analysis of ECR were considered as ECR risk factors. Patients were stratified according to the number of ECR risk factors.

RESULTS

The application of PCI was associated with higher PFR (p=0.008) and OS (p=0.045). However, PCI was not associated with any of the clinical endpoints in multivariate analysis. The competing risk of ICRfirst was significantly decreased with the application of PCI (hazard ratio, 0.476; 95% confidence interval, 0.243 to 0.931; p=0.030). Stage III disease, sequential, and stable disease after thoracic radiation were selected as ECR risk factors. For patients without these risk factors, the application of PCI was significantly associated with increased OS (p=0.048) and a decreased risk of ICRfirst (p=0.026).

CONCLUSION

PCI may play a role in preventing early brain metastasis rather than late brain metastasis after ECR, suggesting that only patients with a low risk of ECR may currently benefit from PCI.

Canadian Consensus Recommendations on the Management of Extensive-Stage Small-Cell Lung Cancer

Small-cell lung cancer (SCLC) is an aggressive, neuroendocrine tumour with high relapse rates, and significant morbidity and mortality. Apart from advances in radiation therapy, progress in the systemic treatment of SCLC had been stagnant for over three decades despite multiple attempts to develop alternative therapeutic options that could improve responses and survival. Recent promising developments in first-line and subsequent therapeutic approaches prompted a Canadian Expert Panel to convene to review evidence, discuss practice patterns, and reach a consensus on the treatment of extensive-stage SCLC (ES-SCLC). The literature search included guidelines, systematic reviews, and randomized controlled trials. Regular meetings were held from September 2022 to March 2023 to discuss the available evidence to propose and agree upon specific recommendations. The panel addressed biomarkers and histological features that distinguish SCLC from non-SCLC and other neuroendocrine tumours. Evidence for initial and subsequent systemic therapies was reviewed with consideration for patient performance status, comorbidities, and the involvement and function of other organs. The resulting consensus recommendations herein will help clarify evidence-based management of ES-SCLC in routine practice, help clinician decision-making, and facilitate the best patient outcomes.

Management of Very Early Small Cell Lung Cancer: A Canadian Survey Study

Concurrent chemoradiotherapy (CRT) is the standard of care for limited-stage small cell lung cancer (LS-SCLC). Local therapy-surgery or stereotactic body radiotherapy (SBRT)-with adjuvant chemotherapy may be appropriate for very early (T1-T2, N0) disease. There is variability in the management of these cases, which may lead to variability in patient outcomes. This study aimed to determine practice patterns for the management of very early LS-SCLC in Canada. A survey was developed and distributed to Canadian medical and radiation oncologists specialising in lung cancer. The survey consisted of three sections: (1) physician demographics, (2) general practice approach, and (3) preferred approach for three clinical scenarios (1: peripheral T1 lesion; 2: central T1 lesion; 3: peripheral T2 lesion). Responses were analysed to detect differences across cases and among physician groups. There were 77 respondents. In case 1, assuming medical operability, most respondents (73%) chose surgery and adjuvant chemotherapy, with 19% choosing CRT. CRT was selected by a higher proportion in case 2 (48%) and case 3 (61%) (p < 0.05). If medically inoperable, most chose CRT over local therapy in all cases, with more choosing CRT in case 2 (84%) and case 3 (86%) than in case 1 (55%) (p < 0.05). Subgroup analysis showed a predilection towards CRT in Western Canada and among more experienced physicians, and towards SBRT in Ontario. There is variability in the management of very early LS-SCLC in Canada. CRT remains the most popular strategy in most cases, with surgery preferred for small peripheral lesions. Larger and more central tumours are more likely to be managed with CRT. Variation in practice is correlated with region and physician experience. Our study illustrates the variability in the management of very early LS-SCLC in Canada and highlights the need for more robust investigations into the ideal approach for these patients.

Real-World Efficacy and Safety of Thoracic Radiotherapy after First-Line Chemo-Immunotherapy in Extensive-Stage Small-Cell Lung Cancer

(1) Background: At present, the efficacy and safety of thoracic radiotherapy (TRT) after chemo-immunotherapy (CT-IT) in patients with extensive-stage small-cell lung cancer (ES-SCLC) still remain unclear. The purpose of this study was to evaluate the role of TRT after CT-IT in patients with ES-SCLC. (2) Methods: From January 2020 to October 2021, patients with ES-SCLC treated with first-line anti-PD-L1 antibody plus platinum-etoposide chemotherapy were enrolled retrospectively. The survival data and adverse events data of patients treated with or without TRT after CT-IT were collected for analysis. (3) Results: A total of 118 patients with ES-SCLC treated with first-line CT-IT were retrospectively enrolled, with 45 patients with TRT and 73 patients without TRT after CT-IT. The median PFS and OS in the CT-IT + TRT group and CT-IT only group were 8.0 months versus 5.9 months (HR = 0.64, p = 0.025) and 22.7 months versus 14.7 months (HR = 0.52, p = 0.015), respectively. The median PFS and OS in all 118 patients treated with first-line CT-IT were 7.2 and 19.8 months with an ORR of 72.0%. In multivariate analyses, liver metastasis and response to CT-IT were shown to be independent prognostic factors of PFS (p < 0.05), while liver metastasis and bone metastasis were independent predictive factors of OS (p < 0.05). Although TRT was significantly associated with better PFS and OS in univariate analysis, the association of TRT and OS failed to reach statistical significance (HR = 0.564, p = 0.052) in multivariate analysis. There was no significant difference in adverse events (AEs) between two treatment groups (p = 0.58). (4) Conclusions: ES-SCLC patients treated with TRT after first-line CT-IT had prolonged PFS and OS with an acceptable safety profile. Further prospective randomized studies are necessary to explore the efficacy and safety of this treatment modality for ES-SCLC in future.

High-Dose Once-Daily Thoracic Radiotherapy in Limited-Stage Small-Cell Lung Cancer: CALGB 30610 (Alliance)/RTOG 0538

PURPOSE

Although level 1 evidence supports 45-Gy twice-daily radiotherapy as standard for limited-stage small-cell lung cancer, most patients receive higher-dose once-daily regimens in clinical practice. Whether increasing radiotherapy dose improves outcomes remains to be prospectively demonstrated.

METHODS

This phase III trial, CALGB 30610/RTOG 0538 (ClinicalTrials.gov identifier: NCT00632853), was conducted in two stages. In the first stage, patients with limited-stage disease were randomly assigned to receive 45-Gy twice-daily, 70-Gy once-daily, or 61.2-Gy concomitant-boost radiotherapy, starting with either the first or second (of four total) chemotherapy cycles. In the second stage, allocation to the 61.2-Gy arm was discontinued following planned interim toxicity analysis, and the study continued with two remaining arms. The primary end point was overall survival (OS) in the intention-to-treat population.

RESULTS

Trial accrual opened on March 15, 2008, and closed on December 1, 2019. All patients randomly assigned to 45-Gy twice-daily (n = 313) or 70-Gy once-daily radiotherapy (n = 325) are included in this analysis. After a median follow-up of 4.7 years, OS was not improved on the once-daily arm (hazard ratio for death, 0.94; 95% CI, 0.76 to 1.17; P = .594). Median survival is 28.5 months for twice-daily treatment, and 30.1 months for once-daily treatment, with 5-year OS of 29% and 32%, respectively. Treatment was tolerable, and the frequency of severe adverse events, including esophageal and pulmonary toxicity, was similar on both arms.

CONCLUSION

Although 45-Gy twice-daily radiotherapy remains the standard of care, this study provides the most robust information available to help guide the choice of thoracic radiotherapy regimen for patients with limited-stage small-cell lung cancer.

Salvage Surgery for Small-Cell Lung Cancer-A Literature Review

(1) Background: Salvation surgery for small-cell lung cancer (SCLC) is exceptionally performed, and only a few cases are published. (2) Methods: There are 6 publications that present 17 cases of salvation surgery for SCLC-the salvation surgery was performed in the context of modern clearly established protocols for SCLC and after including SCLC in the TNM (tumor, node, metastasis) staging in 2010. (3) Results: After a median follow-up of 29 months, the estimated overall survival (OS) was 86 months. The median estimated 2-year survival was 92%, and the median estimated 5-year survival was 66%. (4) Conclusion: Salvage surgery for SCLC is a relatively new and extremely uncommon concept and represents an alternative to second-line chemotherapy. It is valuable because it may offer a reasonable treatment for selected patients, good local control, and a favorable survival outcome.

What Is New in Small Cell Lung Cancer

Small cell lung cancer (SCLC) is a rare yet aggressive lung cancer subtype with an extremely poor prognosis of around 1 year. SCLC accounts for 15% of all newly diagnosed lung cancers and is characterized by rapid growth with high potential for metastatic spread and treatment resistance. In the article the authors review some of the most notable efforts to improve outcomes, including trials of novel immunotherapy agents, novel disease targets, and multiple drug combinations.

Rare thoracic cancers: a comprehensive overview of diagnosis and management of small cell lung cancer, malignant pleural mesothelioma and thymic epithelial tumours

Despite the progress in outcomes seen with immunotherapy in various malignancies, including nonsmall cell lung cancer, the benefits are less in small cell lung cancer, malignant pleural mesothelioma and thymic epithelial tumours. New effective treatment options are needed, guided via more in-depth insights into the pathophysiology of these rare malignancies. This review comprehensively presents an overview of the clinical presentation, diagnostic tools, staging systems, pathophysiology and treatment options for these rare thoracic cancers. In addition, opportunities for further improvement of therapies are discussed.

Use of radiation therapy among patients with Extensive-stage Small-cell lung cancer receiving Immunotherapy: Canadian consensus recommendations

OBJECTIVES

Thoracic radiation therapy (TRT) and prophylactic cranial irradiation (PCI) are commonly used in the management of extensive-stage small-cell lung cancer (ES-SCLC); however, Phase III trials of first-line immunotherapy often excluded these options. Guidance is needed regarding appropriate use of TRT, PCI, and magnetic resonance imaging (MRI) surveillance while new data are awaited.

MATERIALS AND METHODS

In two web-based meetings, a pan-Canadian expert working group of five radiation oncologists and four medical oncologists addressed eight clinical questions regarding use of radiation therapy (RT) and MRI surveillance among patients with ES-SCLC receiving immunotherapy. A targeted literature review was conducted using PubMed and conference proceedings to identify recent (January 2019-April 2022) publications in this setting. Fifteen recommendations were developed; online voting was conducted to gauge agreement with each recommendation.

RESULTS

After considering recently available evidence across lung cancer populations and clinical experience, the experts recommended that all patients with a response to chemo-immunotherapy, good performance status (PS), and limited metastases be considered for consolidation TRT (e.g., 30 Gy in 10 fractions). When considered appropriate after multidisciplinary team discussion, TRT can be initiated during maintenance immunotherapy. All patients who respond to concurrent chemo-immunotherapy should undergo restaging with brain MRI to guide decision-making regarding PCI versus MRI surveillance alone. MRI surveillance should be conducted for two years after response to initial therapy. PCI (e.g., 25 Gy in 10 fractions or 20 Gy in 5 fractions) can be considered for patients without central nervous system involvement who have a response to chemo-immunotherapy and good PS. Concurrent treatment with PCI and immunotherapy or with TRT, PCI, and immunotherapy is appropriate after completion of initial therapy. All recommendations were agreed upon unanimously.

CONCLUSIONS

These consensus recommendations provide practical guidance regarding appropriate use of RT and immunotherapy in ES-SCLC while awaiting new clinical trial data.

Thoracic Radiation in Limited Stage Small Cell Lung Cancer: Trends in Radiation Fractionation

INTRODUCTION

Thoracic radiotherapy (TRT) is standard of care for limited-stage small cell lung cancer (LS-SCLC). Although initial data supported the use of twice-daily (BID) radiation to a dose of 45 Gy, recent trials have suggested similar efficacy with daily fractionation (QD) to a dose of 60 to 70 Gy. This study evaluates trends in treatment regimen in patients treated with TRT for LS-SCLC.

MATERIALS AND METHODS

The National Cancer Database (NCDB) was queried for patients with LS-SCLC treated with TRT between 2004 to 2017 grouped by RT fractionation QD vs. BID. Exclusion criteria were unknown stage, and unknown RT dose. Multivariable (MVA) analyses using logistic regression were performed to investigate factors associated with receipt of a specific fractionation schedule.

RESULTS

A total of 17,453 patients met inclusion criteria, with 4,996 receiving BID treatment and 12,457 receiving QD treatment. The most common QD dose was 60 Gy (48.9%). Overall, QD fractionation has increased (1.3%/year). In 2004, 45 Gy BID treatment (41.4%) was the dominant fractionation. By 2017, 60 Gy QD (45.2%) increased (1.9%/y) to be the dominant fractionation, while 45 Gy BID (24.8%) decreased (-1.4%/y) to be the second most common fractionation. On MVA, factors that affect 1 treatment over the other were further stratified.

CONCLUSION

Since 2004, QD fractionation has been the preferred TRT regimen for patients with LS-SCLC compared to BID fractionation, with the proportion of patients getting QD treatment continuing to increase. The choice of treatment regimen appears to be influenced by both patient and facility characteristics.

Prophylactic cranial irradiation in small cell lung cancer: an update

PURPOSE OF REVIEW

The current review presents recent updates in the seminal literature of research on prophylactic cranial irradiation (PCI) in small cell lung cancer (SCLC).

RECENT FINDINGS

Brain MRI restaging before the administration of PCI reveals a substantial proportion of brain metastasis in baseline brain metastasis free extensive-stage SCLC (ES-SCLC) and limited-stage SCLC (LS-SCLC). Posthoc analyses from the CASPIAN and IMpower133 trials revealed decreases in brain metastasis rates in ES-SCLC treated with chemoimmunotherapy relative to the brain metastasis rates in ES-SCLC treated with chemotherapy alone. A recent meta-analysis of literature published after the landmark 1999 Auperin meta-analysis confirmed the survival benefit of PCI in LS-SCLC patients. A recent study employing PET before and after PCI demonstrated that hippocampal avoidance -PCI (HA-PCI) preserved the metabolic activity of the hippocampi compared with regular PCI. Two phase III trials evaluating neurocognitive functions after HA-PCI versus PCI have yielded conflicting results. Ongoing clinical trials (MAVERICK, PRIMALung, NRG CC003, NCT04535739, NCT04829708 and NCT03514849) regarding PCI versus MRI surveillance and HA-PCI versus PCI were also discussed.

SUMMARY

Currently, the indications for PCI in SCLC are under question in the modern MRI era. Result from prospective phase III, MRI staged and MRI monitored RCTs are expected to elucidate the role of PCI in LS-SCLC and ES-SCLC. Preliminary results indicated that adding immunotherapy to chemotherapy may reduce brain metastasis rate in SCLC. Further data to this aspect are warranted to determine the role of PCI in the immuno-chemotherapy era. The future direction for PCI should be the comprehensive integration of personalized patient selection, HA-PCI utilization and potential employment of other neurocognitive preservation strategies.

Stereotactic Body Radiotherapy (SBRT) in Very Limited-Stage Small Cell Lung Cancer (VLS-SCLC)

Small cell lung cancer (SCLC) is an aggressive neuroendocrine tumour with metastatic propensity. Stereotactic body radiation therapy (SBRT) is an emerging therapeutic option for SCLC, despite limited supporting evidence. By evaluating the use of SBRT in very limited stage (VLS) SCLC at our institution, we aimed to contribute to the existing knowledge in this area while establishing a basis for further research. We performed a retrospective review of all cases of VLS-SCLC treated with SBRT between 2013 and 2020. Baseline demographics, diagnostic, and treatment information were collected. The primary outcome was overall survival (OS). We identified 46 patients with pathologically confirmed VLS-SCLC; 25 were treated with SBRT, and the remainder received either surgery, conventional radiation therapy, chemotherapy, or palliative-intent therapy. After a median follow-up of 23.7 months, 44% of the patients had died; the median OS was of 24.4 months for the SBRT cohort and 67.0 months for the curative intent non-SBRT cohort. The difference in disease recurrence and survival between cohorts was underpowered and not statistically significant. Higher baseline ECOG and comorbidity was noted in the SBRT cohort.

An Overview of the Role of Radiotherapy in the Treatment of Small Cell Lung Cancer - A Mainstay of Treatment or a Modality in Decline?

AIMS

Small cell lung cancer (SCLC) accounts for about 15% of all lung cancers. Chemotherapy, immunotherapy and radiotherapy all play important roles in the management of SCLC. The aim of this study was to provide a comprehensive overview of the role and evidence of radiotherapy in the cure and palliation of SCLC.

MATERIALS AND METHODS

The search strategy included a search of the PubMed database, hand searches, reference lists of relevant review articles and relevant published abstracts.

CLINICALTRIALS

gov was also queried for relevant trials.

RESULTS

Thoracic radiotherapy improves overall survival in limited stage SCLC, but the timing and dose remain controversial. The role of thoracic radiotherapy in extensive stage SCLC with immunotherapy is the subject of several ongoing trials. Current evidence supports the use of prophylactic cranial irradiation (PCI) for limited stage SCLC but the evidence is equivocal in extensive stage SCLC. Whole brain radiotherapy is well established for the treatment of brain metastases but evidence is rapidly accumulating for the use of stereotactic radiosurgery. Further studies will define the role of PCI, whole brain radiotherapy and hippocampal avoidant PCI in the immunotherapy era.

CONCLUSION

Radiotherapy is an essential component in the multimodality management of SCLC. Technological advances have allowed safer delivery of radiotherapy with reduced toxicities. Discussion at multidisciplinary team meetings is important to ensure radiotherapy is considered and offered in appropriate patients.

PARP inhibitor plus radiotherapy reshapes an inflamed tumor microenvironment that sensitizes small cell lung cancer to the anti-PD-1 immunotherapy

Small cell lung cancer (SCLC) is a highly malignant tumor with extremely poor prognosis. The treatment strategy is very limited, and patient outcomes remain dismal with the 5-year survival rate being mere 3-6%. Thus, novel therapeutic strategies for SCLC patients are urgently needed. In this study, we found that the triple-therapy of poly (ADP-ribose) polymerase (PARP) inhibitor, radiotherapy (RT) and anti-PD-1 treatment significantly inhibited tumor growth and prolonged survival in the syngeneic SCLC models in immunocompetent C57BL/6 mice. Mechanistically, we demonstrated that the combination of PARP inhibitor niraparib and RT reshaped an inflamed tumor microenvironment, including activation of the cGAS/STING immune response pathway, induction of immunogenic cell death, and upregulation of PD-L1 on tumor cells. Furthermore, this triple-therapy substantially augmented CD8⁺ T cell infiltration and activation, and enhanced anti-tumor effects as revealed by increased median survival time and reduced tumor volume without additional myelosuppression or hepatic injury. Together, our studies demonstrated that PARP inhibitor combined with RT potentiated anti-tumor immunity and enhanced the efficacy of anti-PD-1 immunotherapy in preclinical study, which provided a promising therapeutic strategy for SCLC patients in clinic.

Different clinical characteristics and survival between surgically resected pure and combined small cell lung cancer

BACKGROUND

Small cell lung cancer (SCLC) is the most malignant and common form of neuroendocrine lung cancer with pure (P-SCLC) and combined subtypes (C-SCLC). However, little is known about the differences between these two groups and in this study we aimed to provide a more comprehensive insight into SCLC.

METHODS

Data from 580 postoperative patients with pathologically confirmed SCLC in Shanghai Chest Hospital from January 2010 to December 2020 were collected retrospectively. The clinical characteristics and prognosis were analyzed.

RESULTS

A total of 357 P-SCLC patients and 223 C-SCLC patients were included. The results indicated that P-SCLC appeared to have a higher proportion of being located in the middle lobe than C-SCLC. The incidences of P-SCLC in patients with visceral pleural invasion (VPI) and in stage II were higher than C-SCLC, while C-SCLC was more likely to be accompanied by higher incidences of epidermal growth factor receptor (EGFR) mutation, anaplastic lymphoma kinase (ALK) rearrangement, and higher levels of CEA, SCCA and CYFRA21-1 than P-SCLC. The most common were SCLC combined with large cell neuroendocrine components among 223 C-SCLCs. Survival analysis confirmed a more favorable disease-free survival (DFS) (p = 0.016) and overall survival (OS) (p = 0.024) in patients with P-SCLCs compared with C-SCLCs. Histological type, tumor location, pN stage, adjuvant chemotherapy, serum NSE and CA125 levels were independent risk factors for survival rate in SCLC. In addition, adjuvant chemotherapy was beneficial in improving stage I P-SCLC and C-SCLC DFS and OS rates, and similar results were not seen in adjuvant radiation therapy.

CONCLUSIONS

Patients with C-SCLC have a poorer prognosis than P-SCLC patients. We determined that large cell neuroendocrine carcinoma was the most common additional component of C-SCLC, and patients with this component appeared to have a longer DFS and OS than other combined components.

Sequential Hypofractionated versus Concurrent Twice-Daily Radiotherapy for Limited-Stage Small-Cell Lung Cancer: A Propensity Score-Matched Analysis

Background: As there are no randomized trials comparing twice-daily with sequential hypofractionated (sequential hypo) radiotherapy regimens for limited-stage small-cell lung cancer (LS-SCLC). This study aimed to compare these two regimens for LS-SCLC by propensity score-matched analysis (PSM). Methods: We retrospectively analyzed 108 LS-SCLC patients between January 2015 and July 2019. All patients received concurrent twice-daily or sequential hypo radiotherapy. The survival, failure patterns, and toxicities were evaluated before and after PSM. Results: Before PSM, multivariate analysis showed that patients treated with sequential hypo had a significantly better overall survival (OS) and distant metastasis-free survival (DMFS) (HR = 0.353, p = 0.009; HR = 0.483, p = 0.039, respectively). Total radiotherapy time ≥ 24 days and stage III (HR = 2.454, p = 0.004; HR = 2.310, p = 0.004, respectively) were poor prognostic indicators for OS. Patients with a total radiotherapy time ≥ 24 days and N2−3 were more likely to recur than others (HR = 1.774, p = 0.048; HR = 2.369, p = 0.047, respectively). N2−3 (HR = 3.032, p = 0.011) was a poor prognostic indicator for DMFS. After PSM, being aged ≥65 years was associated with poorer OS, relapse-free survival (RFS) and DMFS (p < 0.05). A total radiotherapy time of ≥24 days was a poor prognostic indicator for OS and RFS (HR = 2.671, p = 0.046; HR = 2.370, p = 0.054, respectively). Although there was no significant difference, the patients in the sequential hypo group had a trend towards a better OS. The failure pattern between the two groups showed no difference. More patients had grade 1−2 esophagitis in the twice-daily group (p = 0.001). Conclusions: After propensity matching, no difference was shown in survival and failure. The sequential hypo schedule was associated with comparable survival and less toxicity and may be used as an alternative to concurrent twice-daily regimens.

Once daily (OD) versus twice-daily (BID) chemoradiation for limited stage small cell lung cancer (LS-SCLC): A meta-analysis of randomized clinical trials

OBJECTIVES

Assess Once daily (OD) chemoradiation effectiveness for LS-SCLC compared with twice daily (BID) chemoradiation.

METHODS AND MATERIALS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline, eligible randomized clinical trials (RCT) comparing OD and BID were identified on electronic databases. A meta-analysis was performed to compare overall survival (OS), progression-free survival (PFS), and toxicity. A metaregression analysis was conducted to explore the influence of fractionation, biological effective dose (BED), the proportion of patients treated with prophylactic cranial irradiation (PCI), elective nodal irradiation (ENI), and the start of radiotherapy (week 1 or week 4).

RESULTS

Five RCTs with a total of 1941 patients (OD vs. BID) were included. The relative risk (RR) for OS and PFS was 0.97 (CI95% 0.8-1.1, p = 0.731) and 0.90 (CI95% 0.7-1.1, p = 0.20) at 3-years. In the metaregression analysis, hypofractionated radiotherapy schedules were associated with an improvement in overall survival (p = 0.03). The start of radiotherapy (W1 or W4), BED, and ENI had no significant effect on OS and PFS. The complete response rate partial response and overall response rate for BID vs OD were 40% vs. 33% (p = 0.97), 50% vs. 57% (p = 0.94), and 89% vs. 93% (p = 0.99). The rate of completed planned RT 96% vs. 94% (p = 0.66), and the % of ≥4 chemotherapy cycles received 74% vs. 74% (p = 0.99), did not differ between OD and BID. The local and distant failure rates were not significantly different between OD and BID 40% vs. 33% (p = 0.88) and 36% vs. 36% (p = 0.99). No difference in grade 2 or grade 3 pneumonitis and esophagitis was observed among the groups (p = NS).

CONCLUSION

For LS-SCLC, OD conventional chemoradiation results in similar outcomes to BID chemoradiation. In contrast, hypofractionated radiotherapy was associated with a better OS and PFS than BID. Additional randomized phase III trials exploring hypofractionation with systemic therapy are warranted to validate our findings.

Immune Checkpoint Inhibitors and Chemoradiation for Limited-Stage Small Cell Lung Cancer

OPINION STATEMENT

Limited-stage small cell lung cancer (LS-SCLC) is a potentially curable disease. However, most patients develop disease relapse shortly after definitive treatment. The landmark trials IMpower133 and CASPIAN demonstrated a survival benefit with the addition of immunotherapy to first-line platinum/etoposide for extensive-stage small cell lung cancer. Therefore, it is critical to determine whether advancements in overall survival with immunotherapy can be translated earlier into the treatment paradigm for LS-SCLC. Decades of robust preclinical research into the synergism of radiation therapy and immunotherapy set the stage for the combination of these treatment modalities. Recently published data suggests tolerability of single agent immunotherapy concurrent with chemoradiation in LS-SCLC, along with promising efficacy. However, combination immunotherapy in the consolidation setting appears too toxic, although this may be reflective of the dosing schedule rather than inherent to any combination immune checkpoint blockade. Here, we review underlying mechanisms of synergy with the combination of radiation and immunotherapy, the safety and efficacy of respective treatment modalities, and the ongoing trials that are exploring novel therapeutic approaches for LS-SCLC. Pivotal trials in LS-SCLC are ongoing and anticipated to aid in understanding efficacy and safety of immunotherapy with concurrent platinum-based chemoradiotherapy.